Parameterising wakes for oceanographic models

This Research Project is sponsored by the Centre for Environment Fisheries and Aquaculture Science (CEFAS) and is part of the EPSRC CDT in Offshore Wind Energy Sustainability and Resilience’s Predicting Offshore Wind wake interactions for Energy and the enviRonment (POWER) Cluster.

The CDT is a partnership between Hull, Durham, Loughborough and Sheffield universities, along with over 40 industry partners. We will welcome over 65 funded doctoral researchers between 2024 and 2028. Join us to tackle some of the biggest research challenges, in a supportive environment where you can grow your own career while you help grow the offshore wind industry.

The offshore wind sector is rapidly expanding to meet net-zero energy demands. Individual turbines and farms are getting larger and further from shore, with individual turbines spanning 240 m in diameter and farms reaching 600 km2. Forced by spatial constraints, but enabled by floating technology, farms are now developing in deeper waters, occupying increasingly vast areas.

Oceanographic flow processes are highly sensitive to sea surface boundary conditions (Christiansen et al., 2022), which are in turn critically dependent on atmospheric forcing. Atmospheric flows past offshore wind turbines produce highly turbulent and extensive wakes. These wakes are a necessary result of energy extraction from the wind, and are a key motivation for spatial planning of offshore wind farms where turbine placement is optimized for maximal energy extraction with minimized costs associated to infrastructure and spatial footprint (Giebel et al., 2016). The turbulent wakes propagate downstream, leading to wake-wake interactions and farm-scale atmospheric flow processes with a significantly reduced wind speed in the lee of an offshore wind farm (Platis et al., 2018).

It has been recently shown that such large-scale atmospheric interactions can have a significant effect on sea-surface conditions, realised through a locally reduced wind shear stress (Christiansen et al., 2022). Large-scale deployment of offshore wind farms in shelf seas therefore poses an emerging oceanographic problem; shelf seas are vital for life on and below water through their control on the vertical transport of nutrients, and are a key component of the biogeochemical cycle (van Berkel et al., 2020). These are crucially dependent on general circulation and water column structure, which are both highly sensitive to conditions at the sea surface (Dorrell et al., 2022). Yet the impact of offshore wind expansion on sea surface conditions and subsequent regional scale effects is poorly understood, and has only recently gained research interest. While wake parameterisations for atmospheric models have received significant interest over the last decade, the current state of the art oceanographic models make sweeping assumptions regarding the form of sea-surface forcing, particularly concerning wake-wake interactions, spatial variability, and turbulent modifications (Christiansen et al., 2022). These limitations must be overcome for accurate model predictions of oceanographic response to offshore wind expansion.

This project aims to advance sea-surface parameterisations of atmospheric offshore wind farm wakes for use in oceanographic models, directly supported by CEFAS and the National Oceanography Centre, using the North-West European Shelf FVCOM model. This aim will be realised through the following objectives:

• Explore literature and gather/generate datasets required for model validation
• Develop and validate wake parameterisations
• Explore the influence of solution sensitivity to model parameters
• Explore the potential impacts of future offshore wind development on North Sea oceanography

Completion of these objectives will deliver a functional oceanographic model for future research into impacts of offshore wind deployment to inform marine spatial planning.

Training & Skills

You will undertake two three-week placements at NOC during the PhD programme to provide support with FVCOM. The first placement will occur at the start of year 2 where the basics of FVCOM will be taught. The second placement will occur at the start of year 3 to learn how to set up and validate FVCOM simulations, and implement parameterisations. There will also be an industry placement opportunity at CEFAS in the final year. Beyond academia, this PhD project will open pathways to a career in physical oceanography, the wind energy sector, or more broadly a career using computational fluid dynamics or data science.

You will benefit from a taught programme, giving you a broad understanding of the breadth and depth of current and emerging offshore wind sector needs. This begins with an intensive six-month programme at the University of Hull for the new student intake, drawing on the expertise and facilities of all four academic partners. It is supplemented by Continuing Professional Development (CPD), which is embedded throughout your 4-year research scholarship.

Entry Requirements

If you have received a First-class Honours degree, or a 2:1 Honours degree and a Masters, or a Distinction at Masters level with any undergraduate degree (or the international equivalents) in psychology, we would like to hear from you.

If your first language is not English, or you require a Student Visa to study, you will be required to provide evidence of your English language proficiency level that meets the requirements of the Aura CDT’s academic partners. This course requires academic IELTS 7.0 overall, with no less than 6.0 in each skill. Please contact auracdt@hull.ac.uk for further guidance or questions.

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